JP2007015160A - Polybutylene terephthalate-laminated paper and paper container using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybutylene terephthalate-laminated paper which does not cause the adhesion of the surfaces and backs of the laminated papers during long-term keeping or the fusion of a mold cavity surface and a polybutylene terephthalate surface when thermoforming and does not form a mold release mark in the molding of a paper container, and to provide the container made of the polybutylene terephthalate-laminated paper obtained by thermoforeming that paper. <P>SOLUTION: A polybutylene terephthalate resin composition, which is prepared by compounding 0.01-5.0 wt.% of a mold release agent (B) with a polyester resin (A), is laminated at least on one side of paper to provide the polybutylene terephthalate-laminated paper. The container made of the polybutylene terephthalate-laminated paper is obtained by thermoforming that paper. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polybutylene terephthalate laminated paper (hereinafter abbreviated as PBT laminated paper) and a paper container using the same. More specifically, the present invention relates to a PBT laminated paper obtained by laminating a polybutylene terephthalate resin composition containing a release agent on at least one surface of paper, and a paper container obtained from the PBT laminated paper.

  In recent years, food cooked by a microwave oven, an oven, or the like has been widely used, and one of the containers is a container in which a thin film of a synthetic resin is laminated on paper (hereinafter abbreviated as a laminated paper container). Laminated paper containers are advantageous in that they are lighter and cheaper than those made of synthetic resin, and can detect contamination of food in a food by a metal detector. Therefore, it is widely used for cooking for cakes, baked goods, etc., for lunch boxes, prepared dishes, and frozen foods sold at stations, convenience stores, grocery stores, and the like. Examples of the synthetic resin used in the laminated paper container include polymethylpentene resin, polyolefin resin, polyester resin, and the like, and polyester resin is preferable from the viewpoint of heat resistance and processability.

  In Patent Document 1, a laminate in which a polybutylene terephthalate resin is laminated as a thin film among polyester-based resins is excellent in heat resistance and moldability, and also has less odor transfer to food. Is described as being suitable as a paper container for cooking. Furthermore, Patent Document 2 discloses that a laminated body in which a specific polybutylene terephthalate resin is laminated on paper has further improved heat resistance. Therefore, a container in which this laminated body is molded is a microwave oven that is cooked at a higher temperature than a microwave oven. However, it is described as being suitable as a heat-resistant paper container that can be used.

However, if a large number of PBT laminate papers are stacked in a flat shape or rolled and stored for a long period of time, the front and back surfaces will be in close contact, or if PBT laminate paper is thermoformed into a container shape, The polybutylene terephthalate resin surface, the paper surface and the polybutylene terephthalate resin surface, or the polybutylene terephthalate resin surface may be fused together. When paying close contact with PBT laminate paper, when releasing from the mold, or when separating individual paper containers formed at once from stacked PBT laminate paper, visually check the adhered or fused parts A trace that can be made (hereinafter, this trace is abbreviated as a mold release trace) remains. This release mark impairs the appearance of the paper container and significantly reduces the value of the product. Although PBT laminated paper that can solve this problem has been desired, neither Patent Document 1 nor Patent Document 2 describes or suggests the problem of mold release marks.
JP-A 64-70620 JP 2000-93296 A

In view of the above circumstances, the present inventors have completed as a result of intensive studies to provide a resin-laminated paper container in which the above-mentioned drawbacks are eliminated. That is, the object of the present invention is as follows.
1. Adhesion between the front and back surfaces of laminated paper when stored for a long period of time, and fusion between the mold cavity surface and polybutylene terephthalate resin surface does not occur when thermoformed, and mold release marks occur when molded into a paper container. To provide a so-called PBT laminate paper excellent in releasability.
2. To provide PBT laminate paper with excellent food preservability and heat resistance.
3. To provide a PBT laminate paper in which a necked-in phenomenon of a molten resin thin film (a phenomenon in which a molten resin thin film contracts immediately after being extruded from a die lip) hardly occurs when manufactured by an extrusion laminating method.
4). To provide a PBT laminated paper container that has no release marks, has a beautiful appearance, has a high commercial value, and is suitable for cooking such as a microwave oven and a microwave oven.

  In this invention, in order to solve the said subject, in 1st invention, 0.01-5.0 weight% of mold release agents (B) with respect to the polyester resin (A) which has a butylene terephthalate repeating unit as a main component. A PBT-laminated paper is provided, wherein the blended polybutylene terephthalate resin composition is laminated on at least one surface of the paper.

  In the second invention, there is provided a PBT laminated paper container which is thermoformed from the PBT laminated paper according to the first invention.

The present invention is as described in detail below, has the following particularly advantageous effects, and its industrial utility value is extremely great.
1. Since the PBT laminated paper according to the present invention is blended with a release agent in a thin-film polybutylene terephthalate resin, a large number of flat sheets are stacked or rolled into a roll and stored for a long period of time. The front and back surfaces do not adhere.
2. The PBT laminated paper according to the present invention can be efficiently manufactured because the molten resin thin film does not cause a neck-in phenomenon when manufactured by an extrusion laminating method.
3. Since the PBT laminate paper according to the present invention is blended with polybutylene terephthalate resin and a release agent, even if it is thermoformed alone, it does not melt onto the mold cavity surface, and a large number of PBT laminate papers are stacked. Even if it is thermoformed, the paper containers do not fuse together and exhibit excellent releasability.
4). The PBT laminated paper container according to the present invention is composed of a resin composition mainly composed of a butylene terephthalate repeating unit, and thus has excellent barrier properties and heat resistance, and is used for long-term storage of foods containing moisture and oil. And as a container for cooking in a microwave oven or microwave oven.
5. Since the PBT laminate paper according to the present invention does not cause mold release marks when thermoformed, the resulting PBT laminate paper container has a beautiful appearance and high commercial value.

  Hereinafter, the present invention will be described in detail. Polyester resin (A) mainly composed of butylene terephthalate repeating units used in the present invention (hereinafter abbreviated as polyester resin (A)). } Means a polyester resin obtained by polycondensation using mainly terephthalic acid or an ester-forming derivative thereof as the polyvalent carboxylic acid component and mainly using 1,4 butanediol as the polyhydric alcohol component. . The main component means that the repeating unit derived from the butylene terephthalate component in the polyester resin (A) is 70 mol% or more in the total polyvalent carboxylic acid unit. If it is less than 70 mol%, the barrier properties and heat resistance are liable to decrease, which is not preferred. More preferably, it is 80 mol% or more, further 90 mol% or more, and most preferably 95 mol% or more.

  As the polyvalent carboxylic acid as a raw material for producing the polyester resin (A) in the present invention, terephthalic acid is used, but it can be used in combination with other polyvalent carboxylic acids. Other polyvalent carboxylic acids include aromatic polycarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, or ester-forming derivatives of these polyvalent carboxylic acids. Examples of the aromatic polycarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, isophthalic acid, phthalic acid, trimesic acid, trimellitic acid, and the like. Acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and the like, and alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid and the like Examples of the ester-forming derivative of carboxylic acid include lower alkyl esters such as dimethyl terephthalate. These polyvalent carboxylic acid components may be used alone or as a mixture of two or more.

As the polyhydric alcohol used when producing the polyester resin (A) in the present invention, 1,4-butanediol is used, but a part thereof may be used in combination with another polyhydric alcohol. Examples of other polyhydric alcohols include aliphatic polyhydric alcohols, aromatic polyhydric alcohols, alicyclic polyhydric alcohols, and polyalkylene glycols. Examples of the aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, pentanediol, hexanediol, glycerin, trimethylolpropane, and pentaerythritol. Examples of the aromatic polyhydric alcohol include bisphenol. A, bisphenol Z and the like, and 1,4-cyclohexanedimethanol and the like as the alicyclic polyhydric alcohol, and polyalkylene glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene. Examples include oxide glycol.

The polyester resin (A) in the present invention can be produced by a conventionally known method. For example, in the case of the melt polymerization method, the polyester resin (A) is obtained by the following method. First, using one or a plurality of esterification reaction tanks, a predetermined amount of a raw material polycarboxylic acid component and a polyhydric alcohol component are charged, and continuously 2 to 5 under a certain range of temperature and pressure conditions. The esterification reaction is allowed to proceed with stirring for a period of time. The temperature in this esterification reaction is 150 to 280 ° C, preferably 180 to 265 ° C, and the pressure is 6.67 to 133 kPa, preferably 9.33 to 101 kPa. Next, the product obtained by the esterification reaction is polycondensed using one or a plurality of polycondensation reaction tanks with continuous stirring for 2 to 5 hours under a certain range of temperature and pressure conditions. Allow to react. The temperature in this polycondensation reaction is 210 to 280 ° C., preferably 220 to 265 ° C., and the pressure is 26.7 kPa or less, preferably 20 kPa or less. The esterification reaction and polycondensation reaction are preferably carried out continuously using a series continuous tank reactor. The polyester resin (A) obtained by the polycondensation reaction is extracted in the form of a strand from an extraction die equipped at the bottom of the polycondensation reaction tank, and is pelletized by being cut with a pelletizer during or after the water cooling step. To be. The types of the esterification reaction tank and the polycondensation reaction tank may be those conventionally known. Examples of the esterification reaction tank include a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower-type continuous reaction tank, and the like. As the polycondensation reaction tank, a vertical stirring polymerization tank, a horizontal stirring polymerization tank, A thin film evaporation type polymerization tank is exemplified. Note that the number of reaction tanks may be one, or a plurality of tanks in which a plurality of tanks are connected in series is not limited to the same type or different types. Furthermore, solid phase polymerization can be added after melt polymerization.

  When producing the polyester resin (A) in the present invention, a catalyst and a reaction aid can be used in the esterification reaction and / or polycondensation reaction. As the catalyst, a titanium compound is usually used, and examples thereof include titanium alcoholate, titanium phenolate, and an inorganic titanium compound. Examples of the titanium alcoholate include tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate. Examples of the titanium phenolate include tetraphenyl titanate. Examples of the inorganic titanium compound include titanium oxide and titanium tetrachloride. It is done. Of these, titanium alcoholate is preferable, and tetrabutyl titanate is more preferable. The amount of the titanium compound used as the catalyst is preferably in the range of 10 to 100 ppm of the polyester resin (A). When the amount used is less than 10 ppm, the polycondensation reaction rate of the polyester decreases, and when the amount used exceeds 100 ppm, the polyester resin (A) may have a neck-in phenomenon during extrusion lamination or after extrusion lamination (A ) Is markedly yellowed, and when the food is stored in a paper container and heated for a long time, the appearance of the paper container and the taste of the food are likely to change. A more preferable range of the amount of catalyst used is 15 to 90 ppm, and a more preferable range is 20 to 70 ppm. Examples of the reaction aid include tin compounds, magnesium compounds, calcium compounds, antimony compounds, germanium compounds, manganese compounds, zinc compounds, zirconium compounds, cobalt compounds, phosphate compounds, sodium compounds, and the like. The catalyst and reaction aid can be recovered from the polyester resin (A) by a method such as wet ashing, and the weight of the recovered catalyst and reaction aid is atomic emission, atomic absorption, ICP (Induced Coupled Plasma). It can be measured by such methods.

  The intrinsic viscosity of the polyester resin (A) in the present invention is preferably in the range of 0.5 to 2.0 dl / g. In the present invention, the intrinsic viscosity is a value calculated from a solution viscosity measured using a mixed solvent of phenol and 1,1,2,2-tetrachloroethane (weight ratio 1: 1, temperature 30 ° C.). is there. When the intrinsic viscosity is less than 0.5 dl / g, the mechanical strength of the molded product is lowered. When the intrinsic viscosity is more than 2.0 dl / g, the extrusion rate from the T-die is reduced when extrusion lamination is performed. Both are unfavorable. A more preferable range of the intrinsic viscosity is 0.6 to 1.8 dl / g, and a more preferable range is 0.7 to 1.5 dl / g. Further, the temperature lowering crystallization temperature of the polyester resin (A) is preferably 175 ° C. or higher. In the present invention, the temperature drop crystallization temperature is the temperature of the exothermic peak due to crystallization that appears when the polyester resin (A) melted at 300 ° C. is cooled in a nitrogen atmosphere at a temperature drop rate of 20 ° C./min. It can be measured using a meter. When the temperature-falling crystallization temperature is less than 175 ° C., the crystallinity is lowered, and the heat resistance of the molded product is likely to be lowered. The temperature drop crystallization temperature is more preferably 180 ° C. or higher.

  The mold release agent (B) used in the present invention functions so as to greatly improve the mold release property of the PBT laminated paper by being blended with the polyester resin (A). In the present invention, the releasability means that the PBT laminate paper is flattened in a large number, stacked or rolled into a roll shape, and the front and back surfaces do not adhere to each other even when stored for a long period of time. This means that it is difficult for mold release marks to occur in the paper container of the product.

Examples of the release agent (B) include hydrocarbon waxes and modified products (b1), higher fatty acid esters (b2), higher fatty acid metal salts (b3), and the like. Examples of the hydrocarbon wax and the modified product (b1) include paraffin wax and polyethylene wax. The paraffin wax is a petroleum wax mainly composed of n-paraffin, and preferably has a melt viscosity at 100 ° C. of 0.1 poise or less and a melting point of 50 to 70 ° C. Polyethylene wax is a low molecular weight polyethylene that has a waxy appearance and has a molecular weight intermediate between paraffin and molding polyethylene. Preferred are those having a number average molecular weight in the range of 500-15000. The higher fatty acid ester (b2) is a compound obtained by esterifying a higher fatty acid and a monohydric or polyhydric alcohol. Examples of higher fatty acids include stearic acid, oleic acid, octanoic acid, lauric acid, ricinoleic acid, behenic acid and the like, and monohydric or polyhydric alcohols include octyl alcohol, myristyl alcohol, stearyl alcohol, behenyl alcohol, glycols, Examples thereof include glycerin and pentaerythritol. Preferred as the higher fatty acid ester (b2) are stearyl stearate, long chain fatty acid triglyceride, long chain fatty acid monoglyceride and the like. As the higher fatty acid metal salt (b3), higher fatty acids such as stearic acid, 1,2-hydroxystearic acid, oleic acid, octanoic acid, behenic acid and ricinoleic acid, and metals such as calcium, magnesium and sodium The compound of this is mentioned. Preferred as the release agent (B) are hydrocarbon waxes and modified products thereof (b1) and higher fatty acid esters (b2), and more preferred are hydrocarbon waxes and modified products thereof (b1). Paraffin wax and polyethylene wax are more preferable, and paraffin wax is more preferable.

The compounding quantity of a mold release agent (B) shall be 0.01 to 5.0 weight% with respect to a polyester resin (A). When the blending amount is less than 0.01% by weight, the releasability is insufficient, and when the thermoforming is performed, the mold cavity surface and the laminated paper container, or the laminated paper containers are fused to each other, When the mold is released from the mold or when the plurality of molded paper containers are individually separated from the stacked state, a mold release mark is generated, so that the appearance of the container is poor and the commercial value is lowered. If the blending amount exceeds 5.0% by weight, bleeding out of the release agent (B) becomes prominent. When blended with the polyester resin (A) and laminated with paper, the adhesion between the two is poor, The mold release agent that bleeds out when thermoformed may contaminate the mold cavity surface or adversely affect the taste of the food stored when used as a paper container. Said mold release agent (B) can be mix | blended individually or in combination of 2 or more types. The more preferable range of the compounding amount of the release agent (B) is 0.05 to 4.0% by weight, and the most preferable range is 0.1 to 3.0% by weight.

In the polyester resin (A) used in the present invention, an inorganic filler, a lubricant, a heat stabilizer, an ultraviolet absorber, a pigment, carbon black, ketjen black, graphite, oxidation, as long as the object of the present invention is not significantly impaired. Various additives such as an inhibitor, a plasticizer and an antistatic agent, and other thermoplastic resins can be blended. Examples of inorganic fillers include fumed silica, clay, kaolinite, talc, glass beads, calcium carbonate, calcium sulfate, aluminum oxide, and titanium oxide. Lubricants include calcium stearate, barium stearate, and zinc stearate. Etc. Other thermoplastic resins include polyethylene, polypropylene, ethylene-α-olefin copolymers, styrenic thermoplastic elastomers, polyphenylene ethers or acid-modified products thereof, polyamide elastomers, polyester elastomers, polyester ether amides, polyether elastomers, Acrylic rubber, core-shell type acrylic rubber, ionomer resin, aromatic polycarbonate, polyamide resin, epoxy resin, or other polyester resin having different terminal carboxyl group concentration, melting point, catalyst amount, etc. from polyester resin (A) .

  The polybutylene terephthalate resin composition used in the present invention contains a release agent (B) and, if necessary, the various additives and / or other thermoplastic resins for the polyester resin (A) described above. It is obtained by doing. The method of blending these may be a conventionally known method. For example, (1) a method of blending in the production process of the polyester resin (A), (2) dry blending into the pellet-shaped polyester resin (A) Method, (3) A master batch premixed with a part of the polyester resin (A) is manufactured and mixed with the remaining polyester resin (A), or (4) Melt-kneading when laminating The method of mix | blending with the inside polyester resin (A), etc. are mentioned.

  The paper used in the present invention includes paper and paperboard based on the classification of the Japan Paper Association and non-woven fabric. Paper based on the classification of the Japan Paper Association includes synthetic base fiber such as processed base paper such as cup base paper, pure white roll paper, wrapping paper such as kraft paper, high quality paper, printing and information paper such as inkjet paper, and polyester fiber. And a functional paper blended with, and examples of the paperboard include coated cardboard. Non-woven fabric is a fiber that is made into a sheet by mechanical and chemical treatment without passing through the form of yarn. Natural materials such as cellulose fibers and synthetic fiber materials such as polyester fibers can be used as raw materials for nonwoven fabrics. Can be mentioned. The paper may be colored on the entire surface, or previously printed with characters, patterns, pictures, etc. on the surface.

  The PBT laminated paper according to the present invention is obtained by laminating the above-mentioned polybutylene terephthalate resin composition in the form of a thin film on paper, and includes those laminated on at least one side and those laminated on both sides. By laminating, functions such as releasability, heat resistance, water resistance, and oil resistance can be imparted to the paper. The PBT laminate layer to be laminated on paper may be only a thin film (one layer) of a polybutylene terephthalate resin composition, or may be a laminate with another resin film or sheet. When laminating the laminate, the polybutylene terephthalate resin composition thin film is placed outside. The surface of the paper on which the polybutylene terephthalate resin composition is not laminated may be left as it is, or a polybutylene terephthalate resin composition, another resin film or sheet, or a laminate thereof may be laminated. Other resin films or sheets may be pre-colored or printed with characters, patterns, pictures, and the like. When a picture or the like is printed on another resin film or sheet and a PBT layer is formed on the surface, the picture is not exposed on the surface, and a PBT laminated paper having a beautiful appearance can be obtained. Examples of other resin films or sheets include thermoplastic resins other than the polyester resin (A), aluminum foil, and the like. The other resin film or sheet may be a foam.

  The laminating method may be a conventionally known method. For example, (1) a method of extruding a melted polybutylene terephthalate resin composition from a T-die into a thin film and laminating it on the paper surface (extrusion laminating method), (2) A method (wet laminating method) in which a polybutylene terephthalate resin composition is formed into a film in advance, and this film is laminated on paper with an epoxy adhesive, an acrylic adhesive, or the like interposed therebetween. More preferable laminating method is (1) extrusion laminating method. When manufacturing by the extrusion laminating method, the melting temperature of the polybutylene terephthalate resin composition extruded from the die lip is preferably in the range of 230 to 320 ° C. When the melting temperature is less than 230 ° C, the polybutylene terephthalate resin composition is insufficiently melted and difficult to extrude into a thin film, so that the thin film may be perforated, and the temperature exceeds 320 ° C. In addition, the polybutylene terephthalate resin composition turns yellow, the neck-in phenomenon occurs, or the meandering of the thin film immediately before lamination to paper increases, so that the take-off speed decreases, which is not preferable. . A more preferable range of the melting temperature is 240 to 310 ° C, a more preferable range is 250 to 300 ° C, and a most preferable range is 260 to 280 ° C. The thickness of the thin-film polybutylene terephthalate resin composition is preferably 100 μm or less on one side. In consideration of productivity and cost, it is more preferably 50 μm or less, and further preferably 30 μm or less.

  When the PBT laminated paper container according to the present invention is stacked in the form of a flat plate of the PBT laminated paper described above, one or many sheets are transferred to a molding die at once, or wound into a roll. In this case, it is obtained by transferring to a molding die while rewinding and thermoforming. The thermoforming method may be a conventionally known method, and examples thereof include a vacuum forming method, a pressure forming method, and a press forming method.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited by the following description examples, unless the summary is exceeded. In Examples and Comparative Examples, the raw materials have the following physical properties, and the characteristic evaluation tests of PBT laminated paper and PBT laminated paper containers were performed by the methods described below.

[raw materials]
(1) Polyester resin (A): produced by a direct polymerization method (melt polymerization method) using terephthalic acid, 1,4-butanediol and a titanium-based polymerization catalyst. A slurry tank equipped with a stirrer, a heating device, a pressure gauge, etc., is charged with 1,4-butanediol at a ratio of 1.8 moles per 1 mole of terephthalic acid in a 50 liter slurry tank. The slurry was prepared by mixing. While continuously feeding this slurry to an esterification reaction vessel adjusted to a temperature of 230 ° C. and a pressure of 78.7 kPa (590 mmHg), the catalyst tetra-n-butyl titanate (50 ppm relative to the theoretical yield of the polymer) (As a solution dissolved in 1,4-butanediol) was continuously charged and the esterification reaction was carried out for 3 hours with stirring to obtain an oligomer having an esterification reaction rate of 97.5%. The obtained oligomer was placed in a first polycondensation reaction tank having a capacity of 100 kiloliters equipped with a stirrer, a heating device, a pressure gauge, etc., adjusted to a temperature of 250 ° C. and a pressure of 2.66 kPa (20 mmHg). The mixture was continuously supplied and allowed to stay for 2 hours under stirring to be polycondensed to obtain a prepolymer having an intrinsic viscosity of 0.250 dl / g. This prepolymer was continuously supplied to a 100-kiloliter double-condensation reaction tank with a temperature adjusted to 250 ° C. and a pressure adjusted to 1.33 kPa (1 mmHg), and allowed to stay for 3 hours under stirring for polycondensation reaction. Further advanced. After completion of the polycondensation reaction, the reaction product is extruded as a strand from a drawing die equipped in the second double condensation reactor, cooled by immersion in cold water at 20 ° C. for 0.9 seconds, and then cut with a cutter. A pellet-shaped polyester resin (A) (polybutylene terephthalate resin) was obtained. The obtained polyester resin (A) had an intrinsic viscosity [η] of 1.20 dl / g and a titanium catalyst amount of 50 ppm. The obtained polyester resin (A) was subjected to various physical property measurements by the methods described below, and the measurement results are shown in Table-1 and Table-2.

(2) Release agent B1: Paraffin wax (manufactured by Nippon Seiki Co., Ltd., trade name: 155 wax).
(3) Release agent B2: monoglyceride (manufactured by Riken Vitamin Co., Ltd., trade name: Riquemar S100A).
(4) Unbleached kraft paper: (manufactured by Oji Paper Co., Ltd., trade name: OK unbleached craft, basis weight 50 g / m ² ).

[Physical properties]
The physical properties of the polyester resin (A) were measured by the following methods.
(1) Intrinsic viscosity [η] (dl / g): After drying the polyester resin (A) for 6 hours with a hot air dryer adjusted to 120 ° C., using an Ubbelohde viscometer, phenol and 1,1,2, , 2-tetrachloroethane mixed solvent (weight ratio 1: 1, liquid temperature 30 ° C.).
(2) Melting point [Tm] (° C.) / Cooling crystallization temperature [Tc] (° C.): About 10 mg of a raw material polyester resin sample was shaved, and a differential scanning calorimeter (manufactured by Seiko Instruments Inc., model: DSC220U) was used. A sample was enclosed in an aluminum pan under a nitrogen atmosphere. The sample was heated at a rate of 20 ° C./min in the range of 30 to 300 ° C., and the melting point [Tm] (° C.) and the cooling crystallization temperature [Tc] (° C.) were measured.

[Characteristic evaluation]
The characteristics of the PBT laminated paper and the PBT laminated paper container were evaluated by the method described below.
(1) Thickness (μm) of thin-film polybutylene terephthalate resin composition: PBT laminated paper produced by the following method is cut at three places at both ends and the center in the width direction, and the cross section is scanned. Using a scanning electron microscope (manufactured by Hitachi, Ltd., model: S-2500), the photograph was taken at a magnification of 1000 times. The portion of the thin-film polybutylene terephthalate resin composition shown in this enlarged photograph was measured using a JIS Class 1 metal ruler, and the average value of the measurement results at three locations was measured as a thin-film polybutylene terephthalate resin composition. The thickness was calculated as
(2) Extrudability: When a PBT laminated paper was produced by the following method, the situation such as the neck-in phenomenon of the polybutylene terephthalate thin film was visually confirmed. “○” indicates that the neck-in phenomenon is the same as when no release agent is blended, and the difference is recognized when the neck-in phenomenon is not blended with a release agent. “△” indicates that the speed had to be reduced, and noticeable meandering and neck-in phenomenon at the end of the thin film immediately before lamination, or perforation in the thin-film polybutylene terephthalate resin composition. The result was determined as “x”.

(3) Releasability: The appearance of a PBT laminate paper container obtained by thermoforming PBT laminate paper by the following method was visually observed and evaluated. No release marks were observed on the paper container, and “◎” indicates that the paper containers were easily separated when separating the overlapping paper containers, “○” indicates that the paper containers were peeled off by hand, The case where the paper containers were not easily peeled off was determined as “Δ”, and the case where the release marks or perforations were observed in the paper container was determined as “X”.
(4) Adhesion: The appearance of the PBT laminated paper container obtained by the following method was visually observed and evaluated. “○” indicates that no peeling was observed between the thin-film polybutylene terephthalate resin composition and the paper, and “×” indicates that peeling was observed between the thin-film polybutylene terephthalate resin composition and the paper. Was determined.
(5) Comprehensive evaluation: For the items (2) to (4) described in [Characteristic evaluation] above, all items judged as “」 ”or“ 」” are given as “、”. Items that were judged as “Δ” or “×” were evaluated as “×”.

[PBT laminate paper manufacturing method]
The polyester resin (A) (polybutylene terephthalate resin) obtained by the method described in (1) above is dried for 6 hours in a hot air dryer set at 120 ° C., and then the following Table-1 (Example) and Table -2 (Comparative Example) was mixed with the release agent and charged into the hopper of a twin screw extruder (manufactured by Nippon Steel Works, model: TEX30HCT, L / D = 30), screw rotation speed 200 rpm, cylinder Pellets were melt-kneaded under conditions of a temperature of 280 ° C. and a discharge rate of 15 kg / hour. The pellets were dried for 6 hours in a hot air dryer set at a temperature of 120 ° C., and then put into a hopper of a 65 mm single screw extruder (manufactured by Musashino Kikai Co., Ltd., L / D = 29). The screw rotation speed was 16 rpm and the cylinder temperature was 280. It was melted under the condition of ° C., adjusted from a T die (die width 850 mm, lip gap 0.6 mm) so that the thickness of the polybutylene terephthalate resin composition was 20 μm and extruded into a thin film. A chill roll (diameter: 650 mm, diameter: 650 mm, temperature adjusted to 30 ° C. of the unbleached kraft paper (width: 600 mm) in the form of a thin-film polybutylene terephthalate resin that is continuously extruded and the roll that is continuously rewound. Sandwiched between a press roll (made of hard rubber, diameter 400 mm, surface length 700 mm) placed with a 70 mm air gap from the T die lip, and taken up at a take-up speed of 150 m / min. The PBT laminated paper which cooled to near vicinity and wound up in roll shape was obtained. In Comparative Example 2, since the meandering of the end of the thin film immediately before lamination was severe, the take-up speed was reduced to 40 m / min to produce a laminated paper.

[PBT laminated paper container manufacturing method]
The PBT laminated paper obtained by the above method is cut into a circular flat plate having a diameter of 100 mm, 15 cut circular flat plates are stacked, and a No. 8 paper plate type male and female mold is placed on the molding machine. Equipped with a molding temperature of 130 ° C., a pressure of 20 MPa, and a molding cycle of 5 seconds. About the obtained PBT laminated paper container, various characteristics evaluation was performed by the above-mentioned method, and the evaluation result was shown to Table-1 and Table-2.

From Table-1 and Table-2, the following becomes clear.
1. When the blending amount of the release agent is within the range of claim 1 (0.01 to 5.0% by weight), extrudability when producing PBT laminate paper, and PBT laminate paper Both mold release and adhesion when thermoformed into a container are excellent (see Examples 1 to 4).
2. When the release agent essential in claim 1 is not blended, the releasability when thermoformed into a PBT paper container is poor, and the obtained PBT paper container peels off the paper containers. It is difficult and the appearance of the product is poor because of the release marks, and the commercial value is low (see Comparative Example 1).
3. Even if a release agent is blended, if the amount is larger than the range essential in claim 1, when producing PBT laminated paper, the meandering of the end of the thin film immediately before lamination is remarkably recognized. The resulting PBT laminate paper container has poor adhesion and low commercial value due to poor adhesion between the paper and the polybutylene terephthalate resin composition (see Comparative Example 2).
4). Since the PBT laminated paper containers of Examples 1 to 4 manufactured with the compounding amount of the release agent within the range of claim 1 are good in extrudability, mold release and adhesion, It was “○”. On the other hand, the PBT paper containers of Comparative Example 1 and Comparative Example 2 manufactured with the compounding amount of the release agent outside the range of claim 1 are poor in extrudability, releasability or adhesion. The overall evaluation was “x”.

Since the PBT laminated paper according to the present invention is excellent in releasability, adhesion, heat resistance, and barrier properties, it can be used as a raw material for molded products such as paper containers for storing foods and the like. The PBT laminated paper container according to the present invention is a food container that needs to be cooked in a microwave oven or microwave oven, such as frozen food or refrigerated food, and a paper container for food that is stored for a long period of time, such as confectionery and beverages. It can be suitably used.

Claims (5)

A polybutylene terephthalate resin composition in which 0.01 to 5.0% by weight of a release agent (B) is blended with respect to a polyester resin (A) whose main component is a butylene terephthalate repeating unit is used on at least one surface of paper. Polybutylene terephthalate laminated paper, characterized by being laminated to 2. The polybutylene terephthalate according to claim 1, wherein the polyester resin (A) having a butylene terephthalate repeating unit as a main component contains 70 mol% or more of butylene terephthalate repeating units in all the polyvalent carboxylic acid-polyhydric alcohol units. Laminated paper. The polybutylene terephthalate-laminated paper according to claim 1 or 2, wherein the release agent is at least one selected from the group consisting of paraffin wax, polyethylene wax, higher fatty acid esters, or higher fatty acid metal salts. The polybutylene terephthalate-laminated paper according to any one of claims 1 to 3, wherein the polybutylene terephthalate-laminated paper is laminated on at least one surface of the paper by an extrusion laminating method. A container made of polybutylene terephthalate-laminated paper, which is thermoformed from the polybutylene terephthalate-laminated paper according to any one of claims 1 to 4.